Vehicle simulators can be used to simulate motions of a vehicle in the real world, such that the feeling conveyed to the driver of the vehicle is as though the driver were actually controlling a vehicle through the real world. In this regard, the prior art discloses vehicle simulators, for example, in which an image projection device is arranged in the driver's field of view and displays an image of the external surroundings of the vehicle to the driver. If the driver of the vehicle simulator then carries out control tasks, such as acceleration, braking or steering inputs, for example, depending on the control input the image of the surroundings displayed on the image projection device is correspondingly adapted to the control inputs and altered. Such simulators are in this case also known for example from entertainment media and in particular from the field of computer games. In addition to stationary simulators, in which merely the represented external image and the alteration thereof result in a simulation of the alteration and/or accelerations of the vehicle being simulated, simulators are also known which have, in addition thereto, a motion system designed for simulating the occurring motions and accelerations within the simulation in a defined motion space. In this case, within the motion space, depending on the type of simulation, up to six degrees of freedom can be mapped by the motion system, namely firstly the three rotational and secondly the three translational motions in the three spatial axes. Particularly in the simulation of aircraft, motion systems are used for the simulator which make it possible to map the motions of the aircraft in all six degrees of freedom within the motion space.
Apart from a few exceptions, the hydraulically or electromechanically driven motion systems are constructed as parallel robots, the most frequently encountered instances of which by far are in turn the arrangement as a hexapod or Stuart platform.
In such simulators having an active motion system, the high-frequency components of the translational accelerations and the high-frequency components of the rotational velocities are directly mapped into the corresponding degrees of freedom, such that these components of the translational accelerations and of the rotational velocities become perceptible directly on the basis of a motion of the motion system. On account of the restricted motion space of the motion system, however, low-frequency components of the translational accelerations and prolonged or constant translational accelerations cannot be mapped directly by a motion of the motion system, but rather are represented by an inclination of the motion platform or of the motion system. This is because, as a result of an inclination of the motion system and thus of the entire simulator relative to the perpendicular to the earth, on account of the constant acceleration due to gravity, the apparent weight vector within the simulator is altered, such that the impression of a prolonged translational acceleration arises with a positional representation of the external surroundings remaining the same.
The reason for this is the fact that the human body is not able to register a translational acceleration quantitatively correctly, and so the ubiquitous acceleration due to gravity can be used for a prolonged translational acceleration in a simulator. For this there is then merely the restriction that a translational acceleration of more than one g can no longer be correctly represented quantitatively.
In addition to the restriction to the acceleration due to gravity in the simulation of prolonged or constant translational accelerations by means of inclination of the motion system, a further problem is that the motion system has to be brought to the final inclination position by a rotational motion. In this case, the rotation rate or inclination rate of the motion system has to be chosen in such a way that the rotation is not perceived by a person in the simulator and is therefore below the perception threshold. However, this restriction generally results in a time delay until the actual simulation of the translational acceleration by inclination of the motion system, which turns out to be all the greater, the greater the jump in the translational acceleration to be simulated turns out to be. In this regard, for example, the take-off of an aircraft initially cannot be correctly mapped quantitatively by a simulator since the translational acceleration at the start approximately corresponds to a jump function and is then present as substantially constant for quite a while. However, since the motion system has to set the inclination angle in such a way that the rotation rate or inclination rate lies below the human perception threshold, a time delay occurs here until the setting of the desired acceleration value to be simulated, and this is often perceived as disturbing. In the extreme case, this ultimately leads to the occurrence of so-called simulator sickness.